README for the MASSES image data for the pointing toward Per-emb-9.

For each tracer, four images are delivered. Images are made using two different Briggs robust parameters of -1 and 1 (robust-1 and robust1).
The robust-1 is higher resolution while robust1 has less noise.
For each robust weighting, one delivered image is not corrected for the primary beam, while the other is corrected for the primary beam (labeled with 'pbcor').
Images not corrected for the primary beam are typically used for mapping structure, while those corrected for primary beam are typically used for measuring accurate fluxes.

The format for each image data cube in a MASSES dataverse is:
[targetname].[linename].robust[weighting].fits
[targetname].[linename].robust[weighting].pbcor.fits

Continuum images are delivered for 1.3 mm and 850 um.
The delivered spectral lines at 1.3 mm are 12CO21, 13CO21, C18O21, and N2DP.
The delivered spectral lines at 850 um are 12CO32, HCOP, H13COP.
This target also has imaged SWARM data at 1.3 mm and 850 um.
At 1.3 mm, the imaged lines are: c3h2, dcn32, dcop32, h2co303, h2co321, h2co322, sio54, so5544, and so5645.
At 850 um, the imaged lines are: 34so9887, cn5232, cn7252, cs76, dcn54, dcop54, h13cn43, hc15n43, hc18o43, hnc43, ocs2827, so7867, and so8877.
Table A3 in the full data release paper indicates which lines are detected for each pointing.

For Per-emb-9, there are three SUB tracks.
Track 151023 was taken with the ASIC correlator.
Track 151024 was taken with the ASIC correlator.
Track 180918 was taken with the SWARM correlator.
For Per-emb-9, there is a single EXT track taken with the SWARM correlator: 161024
No 850 um data was taken in the EXT configuration.
All tracks were combined when imaging.

To import a fits image into miriad, the "fits" task should be used. "op=xyin" should be specified. We show an example for CO(2-1) below:
fits in=Per9.12CO21.robust1.fits out=Per9.12CO21.robust1.cube op=xyin

While casa can directly handle fits image files, to import the file into casa format, the task importfits can be used:
importfits(fitsimage="Per9.12CO21.robust1.fits",imagename="Per9.12CO21.robust1.cube")
